Time may be running out for the Dolans to find a buyer for Cablevision.

With its highest valuation in two years, the $4.8 billion cable operator, founded four decades ago by Charles Dolan, should take advantage of a surge in cable matchmaking to sell, according to Macquarie Group.

Cablevision’s shares have jumped 42 percent in just eight weeks as speculation heated up about cable deals, and shareholders Paulson & Co. and Gamco Investors said a sale is likely.

Cablevision, which tried and failed to take itself private in 2005 and 2007, is dwarfed by larger peers, including Time Warner Cable and Charter Communications.

That puts the company at an even bigger disadvantage if it misses out on the consolidation wave sweeping in.

Charter, backed by billionaire John Malone, is considering combining with Time Warner Cable or Cox Communications, sources have said.

“It’s the perfect setup to sell the company,” Amy Yong, a Macquarie analyst, said of Cablevision. “But they’ve got to act now, because there are definitely other assets in the mix. So if they want to be considered, they should raise their hand.”